This plant was selected from a population of mint seedlings in research plots on land near Monmouth, Oreg. and initially identified as 08-6-10. ‘Chelan Mint’ originated as a seedling from an open pollinated polyploid ‘Black Mitcham’ parent identified as 05-4-9. Diploid ‘Black Mitcham’ peppermint is sterile and only becomes fertile in the polyploidy state. The fertile ‘Black Mitcham’ parent (05-4-9) to ‘Chelan Mint’ was one of several mint lines in a polycross breeding system composed of selected male and female fertile genotypes.